The 2-1 ruling by a panel on the U.S. Court of Appeals for the District of Columbia Circuit could have far-reaching implications for the entire law, which requires most people to buy insurance and requires large employers to offer coverage.

Without the subsidies, fewer people would be required to get coverage. The law mandates only that people obtain affordable insurance, and many people couldn’t afford coverage without the subsidies.

Eliminating the subsidies, which come in the form of a tax credit, also would make employers less likely to cover workers. That’s because employers face penalties only when a worker uses a tax credit to buy insurance on HealthCare.gov, the federal online health exchange created under the law.

Millions of Americans who don’t get insurance through their employer or a government plan purchased coverage through either HealthCare.gov or a state-run exchange during an enrollment period that ended April 15.

State-run exchanges aren’t affected by Tuesday’s court ruling, which is expected to be challenged by the Obama administration. But 34 states -- including Florida -- that did not set up their own exchange and instead relied on the federal exchange could feel the impact.

Almost 1 million Floridians signed up for coverage between Oct. 1 and April 15, more than in any of the other states using HealthCare.gov. Of those, 91 percent -- or about 895,000 -- receive a tax credit to offset the cost of their health premiums.

The average premium in Florida was $347 before the subsidy, according to the Department of Health And Human Services. With the subsidies, the average premium cost Sunshine State consumers $68, or about one-fifth of the full price.

Tuesday’s ruling isn’t retroactive, so people receiving a subsidy won’t have to repay it, even if the administration’s expected appeal isn’t successful.

But opponents of the law hailed the decision as a sign that the 2010 law is beginning to unravel. Less than a month ago, the Supreme Court ruled that closely held corporations don’t have to comply with a requirement that they offer insurance coverage for contraceptives, if they object on religious grounds.

“Once again, a court ruling against ObamaCare has reminded us that this law was poorly conceived, poorly written, and has been poorly executed by an Obama Administration that believes it can just make up and change the rules as it goes,” Republican Sen. Marco Rubio of Florida said in a statement. “ObamaCare is a bad piece of public policy that needs to be repealed and replaced.”

While touring Craig Technologies in Cape Canaveral Tuesday, Gov. Rick Scott noted that the Affordable Care Act caused some people to lose their previous health care plans, even after President Barack Obama said they wouldn’t, and other unforeseen consequences of the law caused patients to lose their doctors and to see their health expenses rise. Scott said the law has led to considerable confusion.

“He has created all of this uncertainty for health care, something that is very important to every family, because of a bad bill,” Scott said. “We have all this opportunity, we ought to be fixing health care.”

Proponents of the law said Tuesday’s ruling means little because it will be challenged. In addition, a separate federal appeals court panel in Richmond issued a unanimous ruling Tuesday -- two hours after the one in the D.C. appellate court — upholding the law and its system of subsidies and tax credits. The conflicting rulings could put the subsidies issue on a path toward an eventual Supreme Court ruling.

“It’s important for consumers to understand that this financial help is still available and this ruling didn’t change that.” said Leah Barber-Heinz, CEO of the statewide consumer health advocacy organization FL CHAIN. “We are confident that when the full D.C. Court of Appeals reviews this case, they will recognize... . that the clear intent of Congress was that marketplace enrollees who qualify for financial help receive it.”

The legal case, filed by a coalition of states, employers and individuals, had been considered a long-shot effort to derail the Affordable Care Act. Federal district judges in the District of Columbia and Virginia previously had ruled for the government.